Shell Programming and Scripting

AIX 6.1
bash shell

Code:

#!/bin/bash -x
STATEMENT="cvs commit -m \"This is\" ../PBP/EIR.ENTRY"
echo $STATEMENT
exit 0

This is the output
+ STATEMENT='cvs commit -m "This is" ../PBP/EIR.ENTRY'
+ echo cvs commit -m '"This' 'is"' ../PBP/EIR.ENTRY
cvs commit -m "This is" ../PBP/EIR.ENTRY
+ exit 0

Problem: Notice the single quotes between "This" and "is" ... This causes the called program "cvs" to think those are separate parameters which they are not.

If I change the shell to this

Code:

#!/bin/bash -x
STATEMENT="cvs commit -m \"This is\" ../PBP/EIR.ENTRY"
echo $STATEMENT
$STATEMENT
exit 0

Then this is the ouput

+ STATEMENT='cvs commit -m "This is" ../PBP/EIR.ENTRY'
+ echo cvs commit -m '"This' 'is"' ../PBP/EIR.ENTRY
cvs commit -m "This is" ../PBP/EIR.ENTRY
+ cvs commit -m '"This' 'is"' ../PBP/EIR.ENTRY
cvs commit: nothing known about `is"'
cvs [commit aborted]: correct above errors first!
+ exit 0

Please do not pass this off as a "cvs" problem. It is not. If I change the script to this

Code:

#!/bin/bash -x
STATEMENT="cvs commit -m \"Thisis\" ../PBP/EIR.ENTRY"
echo $STATEMENT
$STATEMENT
exit 0

Then this is the output
+ STATEMENT='cvs commit -m "Thisis" ../PBP/EIR.ENTRY'
+ echo cvs commit -m '"Thisis"' ../PBP/EIR.ENTRY
cvs commit -m "Thisis" ../PBP/EIR.ENTRY
+ cvs commit -m '"Thisis"' ../PBP/EIR.ENTRY
+ exit 0

How do I get bash to ignore that space?

Did you try to enclose your $STATEMENT into double quote ?

Code:

echo "$STATEMENT"

What are you trying to achieve ?

If you remove the -x option of your bash command, doesn't your script behave the way you expect ?

-x does not make a difference. I have done both -x and +x and no'x' with the same results.

What I need to do is actually execute $STATEMENT

bash does not parse quotes inside quotes or other forms of that sort of doublethink. To make it do so, you use eval.

The reason it doesn't parse quotes inside quotes and the like is the same reason eval tends to be avoided -- parsing syntax inside syntax leaves you open to someone injecting a `rm -Rf ~/` into your input and having your code execute that.

I might try something like this:

Code:

set -- cvs commit -m "This is" ../PBP/EIR.ENTRY

"$@"

...to preserve tokens (not quotes -- the whole point is you don't want quotes) as demanded.

NOTE:
cvs = Concurrent Versions System
commit = commit to the cvs repository
-m = What follows in the quotes is the Log message for this revision
"This is" = the Log message for this revision
./q.sh = the file

This works:

Code:

#!/bin/bash -x
set -- cvs commit -m "This is the comment" ./q.sh 
"$@"
exit 0

What I want to be able to do is dynamically create that whole string in the script and execute it.

This fails

Code:

#!/bin/bash -x
STATEMENT="set -- cvs commit -m \"This is the comment\" ./q.sh "
"$STATEMENT"
exit 0

This fails

Code:

#!/bin/bash -x
STATEMENT="set -- cvs commit -m \"This is the comment\" ./q.sh "
$STATEMENT
exit 0

This is so frustrating because it seems so simple. I am feeling like a not so bright person right now.

(Referring to your last post) Why are you using set -- in the assignment to $STATEMENT?

Try:

Code:

STATEMENT="cvs commit -m \"This is the comment\" ./q.sh "
eval "$STATEMENT"

or, in the spirit of the examples:

Code:

STATEMENT="set -- cvs commit -m \"This is the comment\" ./q.sh "
eval "$STATEMENT"
"$@"